A number of photopolymerizable hydrogel polymers that may be applied to mammalian tissue, including soft, living tissue, in order to treat various medical conditions are disclosed in the following U.S. patent applications:                U.S. patent application Ser. No. 843,485 filed Feb. 28, 1992 (Hubbell et al.) and a continuation-in-part thereof, Ser. No. 08/022,687 filed Mar. 1, 1993,        U.S. patent application Ser. No. 07/870,540 filed Feb. 28, 1992 (Hubbell et al.) and a continuation-in-part thereof, Ser. No. 08/024,657 filed Mar. 1, 1993.        
The hydrogels disclosed in the foregoing applications may be applied to living tissue, for example, for the prevention of post-operative adhesions, the protection of tissue surfaces, the local application of biologically active species, and the controlled release of biologically active agents to achieve local and systemic effects. They also may be used as temporary or long-term tissue adhesives or as materials for filling voids in biological materials. The materials and conditions of application are selected to enhance desirable properties such as good tissue adherence without adverse tissue reaction, non-toxicity, good biocompatability, biodegradability when desired, and ease of application or handling.
The composition that will form the polymerized hydrogel may include a light sensitive polymerization initiator and is applied to the tissue surface in fluent form, as a liquid. The coated tissue then is exposed to light to polymerize the composition and render it non-fluent, in situ. The light is selected to be of an appropriate wavelength to efficiently initiate or sustain the polymerization and is of an appropriate intensity to achieve the polymerization within the desired time.
Reference is made to the above-identified patent applications for a detailed description of various hydrogels usable in this invention, their compositions, manufacture and general use. The disclosures of the above-identified applications are incorporated by reference as part of the disclosure herein.